NAME

pmc_configure_logfile, pmc_flush_logfile, pmc_writelog, pmc_close_logfile — log file management

LIBRARY

Performance Counters Library (libpmc, -lpmc)

SYNOPSIS

#include <pmc.h>

int
pmc_configure_logfile(int fd);

int
pmc_flush_logfile(void);

int
pmc_writelog(uint32_t userdata);

int
pmc_close_logfile(void);

DESCRIPTION

The functions manage logging of hwpmc(4) events.

Function pmc_configure_logfile() is used to turn on and turn off logging. If argument fd is a valid file handle returned by a prior call to open(2) or socket(2) then performance events will be logged to the file corresponding to the specified handle. If the value of argument fd is -1 then logging will be stopped after any pending data is flushed.

Function pmc_flush_logfile() will force all log data queued inside the hwpmc(4) driver to be written out.

Function pmc_writelog() will append a log entry containing the value of argument userdata to the log file.

Function pmc_close_logfile() will flush all pending log data and close hwpmc(4)'s side of the stream.

RETURN VALUES

Upon successful completion, the value 0 is returned; otherwise the value -1 is returned and the global variable errno is set to indicate the error.

ERRORS

A call to pmc_configure_logfile() may fail with the following errors:

[EAGAIN]: The hwpmc(4) driver was not able to create a helper process due to system limits being reached.
[EBUSY]: Function pmc_configure_logfile() was called with a log file already configured.
[EINVAL]: Function pmc_configure_logfile() was called with an argument of -1 without a log file being previously configured.
[ENOMEM]: The system encountered a memory shortage when servicing this request.

A call to pmc_flush_logfile() may fail with the following errors:

[EINVAL]: Function pmc_flush_logfile() was called without a log file being previously configured.

A call to pmc_writelog() may fail with the following errors:

[EINVAL]: Function pmc_writelog() was called without a log file being previously configured.
[ENOMEM]: The system encountered a memory shortage when servicing this request.